Easily dyeable polyolefin composition



United States Patent Office Patented Dec. 29, 1970 U.S. Cl. 26093.7 14Claims ABSTRACT OF THE DISCLOSURE An easily dyeable polyolefincomposition comprising (a) a polyolefin; (b) a compound having a basicnitrogen atom; and (c) an inorganic compound. Both (b) and (c) are of aparticle size less than 1 micron and are present in amounts of 0.5-20wt.percent provided however that (c) is present in an amount of more than/3 the amount of (b).

It is an object of the present invention to provide a polyolefincomposition which is excellent in dyeability.

Notwithstanding that conventionally polyolefins, for example, such asstereo-regular polypropylene, polybutene or high density polyethylenehave a number of advantages from the viewpoint of physical property, itis very diflicult to dye articles thereby with deep color as well aswith fastness because of their molecular structure in which no polargroup is contained. This has heretofore been a great hinderance inutilizing their usefulness.

It is well known that there have been many studies attempted onimprovements in dyeability of such hardly dyeable polyolefins asmentioned above.

Some of these studies have already been made public in the form ofpatent or others. For example, there may be mentioned a method whichrelies on introduction of a polar group into the molecule by subjectingpolyolefin shaped articles to chemical treatment. Which relies onincorporating a high molecular weight substance having a polar groupinto a polyolefin before shaping the polyolefin in order to dye theshaped polyolefin mainly with disperse dyes, which relies onintroduction of a basic nitrogen compound into a polyolefin beforeshaping the polyolefin in order to dye the shaped polyolefin mainly withacid dyes, and which relies on incorporating a metal compound into apolyolefin before shaping the polyolefin in order to dye the shapedpolyolefin with a special mordant dye by utilizing a polyvalent metal ofsaid metal compound as a dyeing seat of said mordant dye. These methods,however, sutfer from such many drawbacks from the industrial point ofview that it is difficult to obtain a uniform composition, that forms ofthe shaped polyolefin compositions are subject to limitation, that aspecial mixing method is required for preparing polyolefin material,that a special dyeing method is required for dyeing the shapedpolyolefin, that sufficient dyeing cannot be effected without subjectingthe shaped polyolefin to special chemical treatment before dyeing, andfurther from that additives contained in the polyolefin composition bledout therefrom during heating or dyeing step.

Furthermore, there are many cases which involve that even if asatisfactorily dyed product can be obtained with a certain kind ofdyestuff, the satisfactorily dyed product cannot be obtained similarlywhen dyed with a dyestutf having different color hue from the former, orin some cases, since the shaped polyolefin can be dyed only with adyestuff having a special chemical structure, the dyeing method thereofand color hue of the dyed product must be subject to restrictions.

In addition, in case the additives are incorporated into the polyolefincomposition before shaping, it is required that these additives mustwithstand ordinary molding temperature and be colorless, and furtherthat various kinds of dyestuffs in large amounts must be dyed on to thepolyolefin shaped articles by addition of these additives in relativelysmall amounts. For these reasons, the kind of those additives employedis particularly limited. Still further, even if such additives satisfythese requirements, their dye adsorption ability is greatly reduced whenthey are contained in the polyolefin resin. For instance,notwithstanding that an additive itself alone absorbs a very largeamount of acid dyestuif, the shaped product obtained by melting andincorporating the additive in the polyolefin resin may be dyed withdisperse dyes even to some extent, but it can hardly be dyed with theimportant acid dyes. Even when dispersion property of said additive isimproved by using at the same time a multivalent metal salt of higherfatty acid such as aluminum sterate or cadmium sterate, merely thedyeability of the shaped polyolefin composition is improved to a certainextent for disperse dyes, but no substantial effectiveness thereof canbe seen for acid dyes in some cases. Accordingly, there are stillremained such inconveniences that inevitably the additive must be usedin an excess amount or the shaped article must be subjected to a specialchemical treamen after shaping step. Further, the additive must be asubstance rich in polarity from necessity of absorbing a large amount ofdyestulf as mentioned above, and consequently the incorporation of alarge amount of said additive in polyolefin resin which is perfectly ofnonpolarity results in a difiiculty from shaping operation. Still more,this may tend to have an adverse influence upon the inherentiallyexcellent mechanical properties of polyolefins.

Extensive investigations for many years by the present inventors forovercoming such various difficulties as mentioned above have resulted inthe present invention, Wherein a polyolefin composition which canreadily be dyed with anionic dyestulfs With deep color as well as withfastness could be provided by reducing an amount of polar substance tobe added thereto, which has an active point of dye absorption. That is,the present invention relates to a polyolefin composition excellent indyeability which is characterized by the fact that the material (A)consisting of a kind of compounds (but aminotriazol and relatedsubstances being excluded) which contain a basic nitrogen atom in theirmolecules or a kind of two or more kinds of them, and the inorganiccompound (B) consisting of a kind of members selected from the groupconsisting of lithium carbonate, strontium carbonate, calcium carbonate,potassium carbonate, magnesium carbonate, basic magnesium carbonate,zinc carbonate, magnesium hydroxide, zinc hydroxide, calcium silicate,magnesium oxide and zinc oxide, each having an average particle size ofless than 1 micron, or a mixture of two or more kinds of them, are mixedwith a polyolefin in amounts of 0.5- 20% by weight, respectively basedon the weight of the polyolefin composition in such a manner that (B) iscontained therein in an amount of more than /3 times the amount of (A).

The compounds having a basic nitrogen atom in their molecules which canbe used in the present invention includes all the substances exceptaminotriazol and related substances, for instance, there may bementioned the following.

(1) Amines represented by the general formula wherein R is an alkyl orcycloalkyl group having 8 or more of carbon atoms, and R and R arerespectively hydrogen atom, alkyl group, aryl group, aralkyl group orderivatives thereof. Concrete examples thereof include such asoctadecylamine, dihexadecylamine, dihexadecyl methylamine, dioctadecylmethylolamine, octylbenzylamine and N-octadecylaniline. Particularly,such tertiary amines, in which R R and R are respectively alkyl orcycloalkyl group having 8 or more carbon atoms, or derivatives thereof,afiord good result. As typical example of such compounds, there may bementioned trioctylamine, tridodecylamine and the like. Furthermore, Rand R may form a closed ring or its derivative. Example of suchcompounds includes N-octylpiperidine, N-undecylpiperidine and the like.

(2) Pyridine derivatives.As example of pyridine derivatives, there maybe mentioned 2-methyl S-ethylpyridine and Symtri (4-pyridyl) cyclohexanwhich is a trimer of vinylpyridine.

(3) Ammonium salt represented by the general formula wherein R is analkyl or cycloalkyl group consisting of 8 or more carbon atoms, R R andR are respectively hydrogen atom, alkyl, aryl or aralkyl group orderivative thereof, and X is chlorine, bromine, carboxylic acid,sulfonic acid or anion of anion surface active agent.

Examples of these compounds include octadecyl ammonium acetate,didodecyl ammonium chloride, dioctyl ammonium octadeeylate,octyldimethyl ammonium bromide, and trioctyl ammoniumdodecylbenzensulfonate.

(4) High molecular weight substances having in their molecule more than1 1O gram equivalent per gram of a nitrogen atom capable of being formedin the form of ammonium ion in the acid aqueous solution of pH 2.

For instance, the following polymers may be exemplified. Polymers ofvinyl monomer having a basic nitrogen typified by vinylpyridine.N-vinylcarbazol, N,N-diethylamino ethylmethacrylate, etc., andcopolymers having at least one of these vinyl monomers as a constituentand denaturants thereof. Homopolyamide and copolyamide such aspoly-e-caprolactum, polyhexamethyleneazipamide andpolyhexamethylenesebacamide having amino group at the terminal ofpolymer, or denaturants thereof. Polyalkyleneimine such aspolyethyleneimine, polypropyleneimine, etc. and derivatives thereof.Reaction products of epichlorohydrin with amino and/or diamines(including piperazine and piperazine derivatives). Condensation polymersof polyamide, polyester, polyurethane, polycarbonate, etc., having intheir main chain a basic nitrogen and having as constituent one or moredicarboxylic acid, glycol or diamine selected from the group consistingof dicarboxylic acid having a basic nitrogen atom such asisocinchomeronic acid, N-methyl di (carboxyethyl) amine, etc., glycolhaving a basic nitrogen atom such as 2,5-dimethylolpyridine, and primaryor secondary diamine having one or more tertiary amine such assym-N-methyl diethylenetriamine. Polymers into which a basic nitrogenatom is introduced by means of chemical denaturation of polymer havingthiuram salt obtained by thiourea treatment of polyvinyl alcohol,polymer having dihydroimidazol obtained by ethylenediamine treatment ofpolymethylmethacrylate, etc. These polymers must have more than 1X10"gram equivalent per gram of the so-called basic nitrogen atom. It isalready well known from a number of proposals that polyolefin shapedarticle can be endowed with dyeability by melt-shaping the same inadmixture with compounds having a basic nitrogen atom in their molecule.The present invention has made further improvements in these methods,thereby to produce a easily dyeable composition having very high valuefrom the industrial point of view.

That is, when compound having a basic nitrogen atom is added and admixedwith polyolefin according to conventionally proposed methods, even ifsaid compound has high affinity to a dyestuff employed, it is a usualmanner to increase the amount of said compound to be added or tochemically treat the obtained shaped article after shaping thecomposition in order to improve dyeing properties thereof, becausedyeing properties of said compound is remarkably reduced whenincorporated in polyolefin. Still more, the additives contained in thecomposition is bled out therefrom during heating step before dyeing orduring dyeing process depending upon the kind of compound having a basicnitrogen atom, and the dyeings are found to be poor in color fastness towashing, and further, those methods are subject to frequent hinderancesof various sorts.

However, in accordance with the present invention it has been found thatwhen fine-powder inorganic compound having average grain size of lessthan 1 micron is added together with these compounds having a basicnitrogen atom in a specific proportion as defined in the presentinvention to polyolefin, such hinderances as mentioned above can beeliminated, whereby a dyed product with deep color and distinctness. Ithas heretofore not been known at all that a composition havingremarkably improved dyeability can be obtained by a combination of acompound having a basic nitrogen atom and finepowder inorganic compound,and the reason why the composition of the present invention drasticallyincreases its rate of exhaustion of dyestutf, particularly aniondyestuff, has been unknown. As the result of extensive studies on thesubject, the present inventors have found the effect as mentioned above,which have resulted in the present invention.

Fine powders of inorganic compound used in the present invention arethose having the average particle size of less than 1 micron selectedfrom the group consisting of lithium carbonate, strontium carbonate,calcium carbonate, barium carbonate, magnesium carbonate, basicmagnesium carbonate, zinc carbonate, magnesium hydroxide, zinchydroxide, calcium silicate, magnesium oxide and zinc oxide. Amongstthese inorganic compounds, those having grain size of less than 0.2micron particularly give good results. Furthermore, calcium carbonateand basic magnesium carbonate are excellent as compared with othercompounds, which are preferably used in the composition of the presentinvention. These compounds are not always necessarily to be chemicallypure, for instance, in the case of calcium carbonate, there may be usedordinary precipitated calcium carbonate or finely pulverized naturalcalcite, marble, lime stone, etc. The surface of these fine powder maybe treated with, for instance, polyolefins or higher fatty acids ormetal salts thereof for the purpose of prevention of coherence and otherpurposes. In case, light stabilizer, thermal stabilizer or fluorescentwhitening agent, etc., is added to the composition, the surface offine-powder inorganic compound may be treated previously with theseadditives.

In obtaining the composition of the present invention, the amounts ofcompound (A) having a basic nitrogen atom and fine-powder inorganiccompound (B) are 0.5- 20% by weight respectively based on the Weight ofthe composition, preferably l-% by weight. Furthermore, it is necessarythat (B) is contained in such a manner that the amount of (B) is to bemore than /3 times the amount of (A). When the amount of (B) is lessthan /3 times the amount of (A), the effect for improving dyeability ofpolyolefin is significantly reduced.

The method of the present invention will be explained in detail below.(Hereinafter (A) represents a compound having a basic nitrogen atom, and(B) represents finepowder inorganic compound as defined in the claim.)

In practicing the present invention, incorporating and admixing (A) and(B) into polyolefin can be readily accomplished by presently availableordinary means, for example, by using a kneading roller, mixer, blenderor extrusion type mixer, etc., and no special means are required. (B) isreadily dispersed homogeneously when kneaded in a melt of polyolefin,and in this case further promotes dispersion of (A) which coexiststherewith. This effect is significantly observed in particular in case(A) is a high molecular weight polymer. When (B) is not added, not onlya relatively large amount of (A) is required to be added in order to adyed product having the same deepness of color but also dyeability ofsaid dyed product tends to fluctuate depending upon the state ofdispersion of (A). Advantageously, however, such fluctuation can beavoided by the addition and mixing of (B) thereto. There is observed atendency that high chroma of color of the dyeings is rather improvedwithout causing substantial deterioration thereof by the addition andmixing of (B). Furthermore, (A) and (B) may be used respectively bypreviously mixing with a part of polyolefin at a temperature nearby ofabove the melting point of polyolefin, or (B) may be mixed with (A) andthen the mixture is added to a polyolefin substance.

The composition of the present invention display good dyeability todyestuffs, particularly to commonly used anion dyestuffs. It is aprominent characteristic of the present invention that a remarkableeffect can be exhibited by dyeing the shaped articles of the compositionof the present invention with commonly used dyestuffs such as acid dyes(including 1:1 type and 1:2 type metallised dyes) direct dyes and acidmordant dyes. Dyeing method for dyeing the composition of the presentinvention is not particularly defined, the dyeing may be accomplishedaccording to ordinary acid dyeing method, particularly use ofhalogenated acetic acid, benzyl halide and aromatic carboxylic acid asdyeing assistants is desirable to reduce a pH of a dye bath.Furthermore, percentage of dye exhaustion of the shaped article to bedyed is increased by treating the shaped product with an aqueoussolution or dispersion in-water solution of the aforesaid dyeingassistants before the dyeing. In dyeing a polyolefin composition intowhich a high molecular weight polymer having a basic nitrogen atom isincorporated, it has been known that the polyolefin composition ispreviously pretreated with, for example, chemical agents which arereactive into additives such as formation or epichlorohydrin. When thistreatment is applied to the composition of the present invention, insome cases the effect thereof is further enhanced significantly.

The compositions used in the present invention include, as polyolefin,any of polymers such as polyethylene, polypropylene, polybutene,poly-3-methylbutene-l, poly-4- methylpentene-l, etc., or copolymershaving two kinds or more of olefins as a unit of constituents. Thepolyolefin composition may be shaped into any form such as film, sheet,fiber and so on. In cases of fibers of polypropylene andpoly-4-methylpentene-1, the characteristic of the present invention isexhibited in particular.

The present invention is explained in more detail by referring to thefollowing examples.

6 EXAMPLE 1 Ninety parts of powder of crystalline polypropylene(viscometric average molecular weight: about 120,000) was meltmixed at230 C. with 5 parts of actadecylamine and 7 parts of calcium silicatehaving average particle size of less than 0.1 micron to obtain pellets.The pellets were melt-spun at 250 C. and drawn at 3 times the originallength to obtain fibers of about 7 d. monofilament. 20 g. of the fiberswas dyed in 1 l. of acid solution containing 10 g. of monochloroaceticacid with 0.6 g. of Cl. Acid Orange 7, 15510, at 100 C. for minutes toobtain a fresh reddish orange dyeing. The percentage of dye exhaustionwas more than 90%.

On the other hand, in the case where the amount of calcium silicateadded was reduced to less than 0.5%, the percentage of dye exhaustionwas very poor and there was observed a large amount of tacky material oforange color being adhered onto the surface of the dyed fibers.

EXAMPLE 2 Three parts of trioctylamine and 3 parts of precipitatedcalcium carbonate having average particle size of less than 0.05 micronwere mixed with parts of pellets of crystalline polypropylene(viscometric average molecular Weight: about 120,000) which wasstabilized against light and heat by previously incorporating therein0.3 part of 2-hydroxy-4-n-octoxybenzophenol, 0.25 part ofdilaurylthiodipropionate and 0.25 part of 2,2-methylene-bis (4-methyl-B-tert-butylphenol). The mixture was kneaded with Banbury mixerand then cut into the form of pellet. The pellets were melt-spun at 230C. and drawn at 3 times the original length at C. to obtain fibers ofabout 3 d. of monofilament. 20 g. of the fibers was dyed in 1 l. of acidsolution containing 4 g. of salicyclic acid with 0.6 g. of Cl. AcidOrange 7, 15510, at 100 C. for 90 minutes to obtain a fresh reddishorange dyeing. The percentage of dye exhaustion was more than 90%.

On the other hand, in the case where the amount of precipitated calciumcarbonate added was reduced to less than 0.5%, the percentage of dyeexhaustion was less than 60%, and there was observed a large amount oftacky material of orange color being adhered onto the surface of thedyed fibers.

EXAMPLE 3 Five parts of undecylpiperidine and 5 parts of magnesium oxidehaving an average particle size of 0.1 micron were kneaded and admixedin 100 parts of pellets of polypropylene having viscometric averagemolecular weight of about 120,000 and the kneaded compound was out intothe form of pellet. The pellets were extruded at an extrudingtemperature of 250 C. to obtain a sheet having about 0.2 mm. thickness.The sheet was biaxially stretched to about 1.5 times the originallength. The film obtained was dyed in l l. of solution containing 4 g.of salicyclic acid with 0.6 g. of Cl. Acid Orange 7, 15510, at 100 C.for 90 .minutes to obtain a fresh reddish orange dyeing. The percentageof dye exhaustion was more than 90%. The dyed film obtained from thecomposition in which magnesium oxide has not been incorporated, and wasfound to have a large amount of tacky material of orange color beingadhered onto the surface thereof.

EXAMPLE 4 In Example 3, sym-tri (4-pyridyl) cyclohexane was used inplace of undecylpiperidine to obtain polypropylene fiber. The dyedproduct which was dyed under the same conditions as in Example 3 hasbeen found to be deeply colored and fresh. In this example, the dyedsheet obtained from the compoistion in which the precipitated calciumcarbonate was not incorporated was found to be dyed with the dyestuffonly at the surface thereof, and color was unclear and pale.

7 EXAMPLE In Example 2, zinc hydroxide and dodecyltrimethyl ammoniumacetate were used in place of the precipitated calcium carbonate andtrioctylamine, respectively, to obtain polypropylene fibers. 20 g. ofthe fibers was dyed in 1 l. of acid solution containing 6 g. of benzoicacid with 0.6 g. of C.I. Acid Red 111, 23265, at 100 C. for 90 minutesto obtain a fresh red dyeings. The percentage of dye exhaustion was morethan 90%. In the case of dyed product obtained from the composition inwhich zinc hydroxide was not incorporated, the percentage of dyeexhaustion was very low, and there was observed a large amount of tackycolored material being adhered onto the surface of the dyed fibers.

EXAMPLE 6 Ninety parts of powder of crystalline polypropylene(viscometric average molecular weight about 130,000) was melt and mixedat 230 C. with 5 parts of copolymer of styrene/2-methyl-5-vinylpyridine(50:50) and 5 parts of lithium carbonate having average particle size ofless than 0.1 micron to obtain pellets. The pellets were melt-spun at260 C. and stretched to three times the original length at 120 C. toobtain the fibers of about 6 d. of monofilament. 20 g. of the fibers wasdyed in 1 l. of acid solution containing 10 g. of monochloroacetic acidwith 0.6 g. of Cl. Acid Orange 7, 15510, at 100 C. for 90 minutes toobtain a fresh reddish orange dyeing. The percentage of dye exhaustionwas more than 90%. On the other hand, in the case where the dyed productdid not contained lithium carbonate, the percentage of dye exhaustionwas very low.

EXAMPLE 7 The same procedures as in Example 6 was repeated except thatcondensation polymer containing in its main chain a piperazine ringobtained by reacting epichlorohydrine with piperazine and stearylaminein the presence of sodium hydroxide was used in place of styrene/2-methyl-S-vinylpyridine copolymer to obtain polypropylene fibers. g. ofthe fibers was dyed in 1 l. of acid solution containing 10 g. of aceticacid with 0.6 g. of CI. Acid Yellow 117, 24820, at 100 C. for 90 minutesto obtain a deep yellow dyeings. The percentage of dye exhaustion wasmore than 95%. On the other hand, in the case of the dyed product whichdid not contain lithium carbonate, the percentage of dye exhaustion wasless than 85%, and there was observed a large amount of tacky materialof yellow color being adhered onto the surface of the dyed fibers.

What is claimed is:

1. A polyolefin composition comprising a polyolefin and mixed therewithat least one amino compound represented by the formula R1 N-R wherein Ris an alkyl or cycloalkyl group having 8 or more carbon atoms and R andR are respectively hydrogen, alkyl, cycloalkyl, aryl or aralkyl and theammonium salts thereof and at least one inorganic compound selected fromthe group consisting of lithium carbonate, strontium carbonate, calciumcarbonate, barium carbonate, magnesium carbonate, basic magnesiumcarbonate, zinc carbonate, magnesium hydroxide, zinc hydroxide, calciumsilicate, magnesium oxide and zinc oxide, each having an averageparticle size of less than 1 micron, said compounds being present inamounts of 05-20% based on the weight of the composition with theproviso that said inorganic compound be present in an amount of morethan /3 times the amount of the amino compound or the ammonium saltthereof.

2. A composition according to claim 1 wherein polyolefin is acrystalline polypropylene, crystalline poly-4- methylpentene-l, orstraight chain polyethylene.

3. A composition according to claim 1, wherein R R and R arerespectively alkyl or cycloalkyl groups having 8 or more carbon atoms.

4. A composition according to claim 1 wherein the amino compound is2-methyl-S-ethylpyridine or sym-tri (4-pyridyl) cyclohexan.

5. A composition according to claim 1, wherein the inorganic compoundshave an average particle size of less than 0.2 micron.

6. A composition according to claim 5 wherein the inorganic compound iscalcium carbonate having an average particle size of less than 0.2micron and same is used in an amount of 1-5 weight percent based on theweight of the composition.

7. Acomposition according to claim 1 wherein the inorganic compound iscalcium carbonate having a particle size of less than 0.2 micron.

8. A composition according to claim 1 wherein the amino compound isN-octylpiperidine or N-undecylpiperidine.

9. A composition according to claim 8 wherein the inorganic compound iscalcium carbonate having a particle size of less than 0.2 micron.

10. A composition according to claim 4 wherein the inorganic compound iscalcium carbonate having a particle size of less than 0.2 micron.

11. A composition according to claim 6 wherein the surface of thecalcium carbonate is coated with a surface treatment agent.

12. A composition according to claim 6 wherein the surface of thecalcium carbonate is coated with a dispersion agent. 7

13. A composition according to claim 6 wherein the surface of thecalcium carbonate is treated with a light stabilizer, thermal stabilizeror fluoroescent whitening agent.

14. A composition according to claim 3, wherein the inorganic compoundis calcium carbonate having a particle size of less than 0.2 micron.

References Cited UNITED STATES PATENTS 3,305,603 2/1967 McIntyre 260-8603,331,806 7/1967 Fior et al. 260 41 FOREIGN PATENTS 728,708 2/1966Canada 26094.9

JOSEPH L. SCHOFER, Primary Examiner S. M. LEVIN, Assistant Examiner US.Cl. X.R.

